The effect of gate recess width on the linearity of GaAs MESFETs

The width of the gate recess was found to greatly effect the linearity of GaAs MESFETs under class AB operation at 850 MHz. The MESFETs with gate-recess spacing larger than 105 nm exhibit poor 3rd order intermodulation and significantly different 5th order intermodulation product dependence on the output power. Good correlation of the discrete device data with the digital amplifier circuit performance was obtained. This work provides insight into a critical parameter for optimum performance of high linearity amplifier applications.